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+layout: post
+title: Namecoin, A Replacement For SSL
+---
+
+This is a long post, and it could very well be two posts disguised as one. I'm
+first going to make a case for namecoins, explaining what they are and why
+they're better than existing solutions. I'm then going to make a case for why
+and how namecoins could be used to replace SSL (amongst other things).
+
+# Bitcoins
+
+This post is about namecoins. But namecoins are based on bitcoins, so you need
+to know how those work first.
+
+If you haven't yet checked out bitcoins, [I highly encourage you to do so][0].
+They're awesome, and I think they have a chance of really changing the way we
+think of and use money in the future. At the moment they're still a bit of a
+novelty in the tech realm, but they're growing in popularity.
+
+The rest of this post assumes you know more or less what bitcoins are, and how
+they work.
+
+# Namecoins
+
+Few people actually know about bitcoins. Even fewer know that there's other
+cryptocurrencies besides bitcoins. Basically, developers of these alternative
+currencies (altcoins, in the parlance of our times) took the original bitcoin
+source code and modified it to produce a new, separate blockchain from the
+original bitcoin one. The altcoins are based on the same idea as bitcoins
+(namely, a chain of blocks representing all the transactions ever made), but
+have slightly different characterstics.
+
+One of these altcoins is called namecoin. Where other altcoins aim to be digital
+currencies, and used as such (like bitcoins), namecoin has a different goal. The
+point of namecoin is to create a global, distributed, secure key-value store.
+You spend namecoins to claim arbitrary keys (once you've claimed it, you own it
+for a set period of time) and to give those keys arbitrary values. Anyone else
+with namecoind running can see these values.
+
+## Why use it?
+
+A blockchain based on a digital currency seems like a weird idea at first. I
+know when I first read about it I was less than thrilled. How is this better
+than a DHT? It's a key-value store, why is there a currency involved?
+
+### DHT
+
+DHT stands for Distributed Hash-Table. I'm not going to go too into how they
+work, but suffice it to say that they are essentially a distributed key-value
+store. Like namecoin. The difference is in the operation. DHTs operate by
+spreading and replicating keys and their values across nodes in a P2P mesh. They
+have [lots of issues][1] as far as security goes, the main one being that it's
+fairly easy for an attacker to forge the value for a given key, and very
+difficult to stop them from doing so or even to detect that it's happened.
+
+Namecoins don't have this problem. To forge a particular key an attacker whould
+essentially have to create a new blockchain from a certain point in the existing
+chain, and then replicate all the work put into the existing chain into that new
+compromised one so that the new one is longer and other clients in the network
+will except it. This is extremely non-trivial.
+
+### Why a currency?
+
+To answer why a currency needs to be involved, we need to first look at how
+bitcoin/namecoin work. When you take an action (send someone money, set a value
+to a key) that action gets broadcast to the network. Nodes on the network
+collect these actions into a block, which is just a collection of multiple
+actions. Their goal is to find a hash of this new block, combined with some data
+from the top-most block in the existing chain, combined with some arbitrary
+data, such that the first n characters in the resulting hash are zeros (with n
+constantly increasing). When they find one they broadcast it out on the network.
+Assuming the block is legitimate they receive some number of coins as
+compensation.
+
+This last step is the crucial piece. Receiving compensation for doing the work
+of putting a block onto the chain is what keeps the bitcoin style of
+crypto-currency going. If there were no compensation there would be no reason to
+mine except out of goodwill, so far fewer people would do it. Since the chain
+can be compromised if a malicious group has more computing power then all
+legitimate miners combined, having few legitimate miners is a serious problem.
+
+In the case of namecoins, there's even more reason to involve a currency. Since
+you have to spend money to make changes to the chain there's a disincentive for
+attackers (read: idiots) to spam the chain with frivolous changes to keys.
+
+### Why a new currency?
+
+I'll admit, it's a bit annoying to see all these altcoins popping up. I'm sure
+many of them have some solid ideas backing them, but it also makes things
+confusing for newcomers and dilutes the "market" of cryptocoin users; the more
+users a particular chain has, the stronger it is. If we have many chains, all we
+have are a bunch of weak chains.
+
+The exception to this gripe, for me, is namecoin. When I was first thinking
+about this problem my instinct was to just use the existing bitcoin blockchain
+as a key-value storage. However, the maintainers of the bitcoin clients
+(who are, in effect, the maintainers of the chain) don't want the bitcoin
+blockchain polluted with non-commerce related data. At first I disagreed; it's a
+P2P network, no-one gets to say what I can or can't use the chain for, and they
+can't stop me! And that's true. But things work out better for everyone involved
+if there's two chains.
+
+Bitcoin is a currency. Namecoin is a key-value store (with a currency as its
+driving force). Those are two completely different use-cases, with two
+completely difference usage characteristics. And we don't know yet what those
+characteristics are, or if they'll change. If the chain-maintainers have to deal
+with a mingled chain we could very well be tying their hands with regards to
+what they can or can't change with regards to the behavior of the chain, since
+improving performance for one use-case may hurt the performance of the other.
+With two separate chains the maintainers of each are free to do what they see
+fit to keep their respective chains operating as smoothly as possible.
+Additionally, if for some reason bitcoins fall out of favor and fall by the
+wayside, namecoin will still have a shot at continuing operation since it isn't
+tied to the former. Tldr: separation of concerns.
+
+# SSL
+
+Time to switch gears. SSL is the mechanism by which web-browsers establish an
+encrypted connection to web-servers. The goal of this connection is that only
+the destination web-browser and the server know what data is passing between
+them. Anyone spying on the connection would only see gibberish. To do this a
+secret key is first established between the client and the server, and used to
+encrypt/decrypt all data. As long as no-one but those parties knows that key,
+that data will never be decrypted by anyone else.
+
+SSL is what's used to establish that secret key on a per-session basis, so that
+a key isn't ever re-used and so only the client and the server know it.
+
+## Public-Private Key Cryptography
+
+There exists something called public-private key cryptography. In this system
+person A has a public and a private key. They can give the public key to anyone
+at all that they want to talk with, doing so can't hurt them. They must keep the
+private key secure from everyone but themselves. If they give their public key
+to person B, then person B can use it to create a message that can only be
+decrypted by the private key. Additionaly, person A can sign messages with their
+private key, so that anyone with the public key can verify that the message came
+from person A and that the contents of the message haven't been tampered with.
+
+There are two problems with public-private key cryptography. First, it's slower
+then normal cryptography where both parties simply share the same key. Second,
+it assumes that the public key given to person B hasn't been tampered with. If
+person C intercepted A's message to B and instead gave B a different public key,
+then when B encrypted a message with that key C would be able to read it instead
+of A.
+
+## How does SSL work?
+
+SSL is at its heart a public-private key system. The client uses the server's
+public key to send the server an encrypted message with the symmetric key it
+wants to use. Since it's only used in the initial setup of the connection to
+negotiate a symmetric key the speed isn't as much of a factor. But getting the
+client the server's public key is.
+
+SSL uses a trust-chain to verify that a public key is the intended one. Your web
+browser has a built-in set of public keys, called the root certificates, that it
+implicitly trusts. These root certificates are managed by a small number of
+companies designated by some agency who decides on these things. These companies
+sign intermediate certificates for intermediary companies. These intermediary
+companies then sign certificates for websites to serve with SSL. So when you get
+a servers SSL certificate (its public key) you also get the signing chain. Your
+browser sees that the server's key is signed by an intermediate public key, and
+that that intermediate public key is signed by one of the root public keys. As
+long as all signatures check out, the public key for the server you're talking
+to also checks out.
+
+## How SSL doesn't work
+
+SSL has a few glaring problems. One, it implies we trust the companies holding
+the root certificates to not be compromised. If some malicious agency was to get
+ahold of a root certificate they could man-in-the-middle any connection on the
+internet they came across. They could trivially steal any data we send on the
+internet. Alternatively, the NSA could, [theoretically][2], get ahold of a root
+certificate and do the same.
+
+The second problem is that it's expensive. Really expensive. If you're running a
+business you'll have to shell out about $200 a year to keep your SSL certificate
+signed (those signatures have an expiration date attached, of course). Since
+there's very few root authorities there's an effective monopoly on signatures,
+and there's nothing we can do about it. For 200 bucks I know most people simply
+say "no thanks" and go unencrypted. The solution is causing the problem.
+
+# Namecoin as an alternative to SSL
+
+There are already a number of proposed formats for standardizing how we store
+data on the namecoin chain so that we can start building tools around it. I'm
+not hugely concerned with the particulars of those standards, only that we can,
+in some way, standardize on attaching a public key (or a fingerprint of one) to
+some key on the namecoin blockchain. When you visit a website, the server
+would then send both its public key and the namecoin chain key to be checked
+against to the browser, and the browser would validate that the public key it
+received is the same as the one on the namecoin chain.
+
+The main issue with this is that it requires another round-trip when visiting a
+website: One for DNS, and one to check the namecoin chain. And where would this
+chain even be hosted?
+
+My proposition is there would exist a number of publicly available servers
+hosting a namecoind process that anyone in the world could send requests for
+values on the chain. Browsers could then be made with a couple of these
+hardwired in. ISPs could also run their own copies at various points in their
+network to improve response-rates and decrease load on the globally public
+servers. Furthermore, the paranoid could host their own and be absolutely sure
+that the data they're receiving is valid.
+
+If the above scheme sounds a lot like what we currently use for DNS, that's
+because it is. In fact, one of namecoin's major goals is that it be used as a
+replacement for DNS, and most of the talk around it is focused on this subject.
+DNS has many of the same problems as SSL, namely single-point-of-failure and
+that it's run by a centralized agency that we have to pay arbitrarily high fees
+to. By switching our DNS and SSL infrastructure to use namecoin we could kill
+two horribly annoying, monopolized, expensive birds with a single stone.
+
+[0]: http://vimeo.com/63502573
+[1]: http://www.globule.org/publi/SDST_acmcs2009.pdf
+[2]: https://www.schneier.com/blog/archives/2013/09/new_nsa_leak_sh.html